Hydraulic actuators

ABSTRACT

AN HYDRAULIC ACTUATOR FOR SUPPLYING LIQUID PRESSURE PULSES TO A HAND APPLIANCE FOR BODY CARE COMPRISES A CYLINDER AND RECIPROCATING PISTON FORMING A WORKING CHAMBER, AN OUTLET PASSAGE CONNECTED TO THE WORKING CHAMBER, AN INLET CHAMBER CONNECTED TO THE WORKING CHAMBER THROUGH AN INLET VALVE, AND PRESSURE REGULATING MEANS FOR BYPASSING A PORTION OF THE LIQUID TO THE INLET CHAMBER ON THE PRESSURE STROKE OF THE PISTON. THE PRESSURE REGULATING MEANS INCLUDES A VALVE HOLDER ADJUSTABLY MOUNTED IN THE INLET CHAMBER AND MOVABLE TOWARD AND AWAY FROM AN OPENING IN THE WORKING CHAMBER OPPOSITE THE PISTON, AND THE INLET VALVE IS MOUNTED THEREIN INSIDE THE ANNULAR REGION OF THE VALVE HOLDER WHICH CLOSES THE OPENING. TAPERED NOTCHES AT THE FRONT END OF THE VALVE HOLDER COOPERATE WITH THE HOUSING TO PROVIDE BYPASS PASSAGES OF PROGRESSIVELY INCREASING CROSS-SECTIONAL AREA AS THE VALVE HOLDER IS MOVED AWAY FROM THE OPENING, AND ARE DESIGNED TO PROVIDE A LINEAR REDUCTION IN LIQUID PRESSURE IN THE OUTLET PASSAGE.   D R A W I N G

March 13, 1973 HYDRAULIC ACTUATORS 3 Sheets-Sheet 1 Filed Sept. 21. 1970Inventors: Michel Antoine More? vw Q Q l H! L .Q

Pierre J. Jousson March 13, 1973 P; J. JOUSSON ET AL 3,720,486

HYDRAULIC ACTUATORS I 3 Sheets-Sheet 2 Y Filed Sept. 21. 1970 m&

Inventors: Michel Antoine Moref Pierre J. Jousson March 13, 1973 P,JOUSSON ET AL 3,720,486

HYDRAULIC ACTUATORS Filed Sept. 21. 1970 3 Sheets-Sheet 3 Pmax Inventars:

Michel Antoine Moret Pierre J. Jousson United States Patent 3,720,486HYDRAULIC ACTUATORS Pierre J. Jousson and Michel-Antoine Moret, Geneva,Switzerland, assiguors to Institut de Recherche WOOG, Geneva,Switzerland Filed Sept. 21, 1970, Ser. No. 74,102 Claims priority,application Switzerland, Sept. 19, 1969, 14,239/ 69 Int. (I1. 130% 21/02US. Cl. 417-440 6 Claims ABSTRACT 01? THE DISCLOSURE An hydraulicactuator for supplying liquid pressure pulses to a hand appliance forbody care comprises a cylinder and reciprocating piston forming aworking chamber, an outlet passage connected to the working chamber, aninlet chamber connected to the working chamber through an inlet valve,and pressure regulating means for bypassing a portion of the liquid tothe inlet chamber on the pressure stroke of the piston. The pressureregulating means includes a valve holder adjustably mounted in the inletchamber and movable toward and away from an opening in the workingchamber opposite the piston, and the inlet valve is mounted thereininside the annular region of the valve holder which closes the opening.Tapered notches at the front end of the valve holder cooperate with thehousing to provide bypass passages of progressively increasingcross-sectional area as the valve holder is moved away from the opening,and are designed to provide a linear reduction in liquid pressure in theoutlet passage.

BACKGROUND OF THE INVENTION The present invention relates to hydraulicactuator units which can be used either as pump units for connection toh'ygiene devices, for example, hydraulic motor driven toothbrushes,water jet devices for eliminating food residues from interdental spacesand gum massaging devices, or hydraulic transmitter devices.

In co-pending application, Ser. No. 736,440, filed on June 12, 1968 nowPat. No. 3,536,065, issued Oct. 27, 1970, an apparatus for body care isdescribed which includes a pump unit having a liquid reservoir, and anelectric motor for driving the pump unit. The pump unit includes areciprocating piston which is driven by the electric motor. The pistonis slidable within a cylindrical part of a working chamber formed in thebody of the pump unit and water is admitted to the working chamber froma reservoir and an inlet chamber, through an inlet valve. Movement ofthe piston in one direction permits water to flow from the inletchamber, via the inlet valve, into the working chamber. Movement of thepiston in the reverse direction causes the inlet valve to close and thewater to be delivered under pressure to a supply conduit.

The pump unit further includes a pressure regulating device whichincludes an orifice which permits Water under pressure from the workingchamber to return to the inlet chamber. The orifice is controlled bymeans of a plunger faced with a resilient insert. By moving the plungerin one sense a small by-pass passage is opened and the pump unittherefore delivers water at a lower pressure through the supply conduit.

In the aforesaid application the pump unit supplies liquid pressurepulses to a unitary hand appliance capable of operation either as anhydraulic toothbrush or as a water jet. The hand appliance includes apiston-type hydraulic motor for driving a toothbrush attachment, orother attachments, and a conduit for supplying the pressure pulses to aWater jet attachment. A valve is provided 7 which is actuable to yieldeither type of operation.

Other similar pump units are known in the art for supplying liquidpressure pulses to separately attachable hand appliances, one of whichis a water jet appliance and the other a toothbrush appliance.

In both the pump unit described in co-pending application, Ser. No.736,440, and in the other known pump unit, there is no discharge valvefor controlling the flow of liquid from the working chamber to thesupply conduit. Both pump units rely on the supply conduit having anadequate length and cross-sectional dimension to prevent sucking hack ofliquid into the working chamber on the suction stroke of the pistonduring water jet operation.

Since there is no discharge valve, and because of the inertiacharacteristics of the flow of liquid, during Water jet operation thereis a tendency for the liquid to continue to flow after the piston hasreached its position of maximum compression and had started to return ona suction stroke. Thus, more water is discharged from the pump than theamount displaced by the piston.

One disadvantage of these pump units, is that the inlet valve ispositioned entirely in the working chamber, that is, the space betweenthe piston and the supply conduit. This gives rise to a high proportionof dead space which adversely etfects the efiiciency of the pump unitand is conducive'to the formation of air bubbles.

Further, the presence of a by-pass passage as described in my co-pendingapplication, Ser.. No. 736,440 is also conducive to the formation of airbubbles.

Air bubbles can cause diificulties when starting the pump units and may,in fact prevent starting altogether. Sometimes the air bubbles can bedispersed by manipulating the pressure regulating device to bleed ordeaerate the pump unit but this is time consuming and not alwayssuccessful.

Air bubbles are particularly troublesome when the hydraulic actuator isused to drive an hydraulic motor in a hand appliance, and an accuratetransmission of a displacement is required.

A second disadvantage found in both the above described known devices isthe difficulty encountered in accurately regulating the pressure of theliquid discharge from the pump units.

SUMMARY OF THE BRESENT INVENTION It is an object of the presentinvention to provide a hydraulic actuator which is small and compact andin which the dead space is reduced to a minimum and the formation of airbubbles reduced.

It is a further object of the present invention, to provide a hydraulicactuator which includes means for accurately regulating the pressure ofliquid discharged from the actuator. The means includes a by-passarrangement, displacement of which, in the body of the actuator, causesa change in the pressure of the liquid discharged from the actuator, thedisplacement and the change in pressure having a linear relationship.

A still further object of the present invention is the provision of anhdraulic actuator, the construction and assembly of which is verysimple.

The present invention employs a reciprocating piston mounted in acylinder to form a working chamber, with an outlet passage connected tothe working chamber for supplying liquid pressure pulses to a handappliance for body care. In accordance with the invention, an opening tothe working chamber is provided opposite the piston, and the inletchamber is on the opposite side of the opening from the piston. Thepressure regulating means includes a valve holder adjustably mounted inthe inlet chamber for movement toward and away from the opening tobypass a portion of the liquid to the inlet chamber on the pressurestroke of the piston. The front of the valve holder has an annularregion adapted to abut a corresponding annular region around the openingtoprevent liquid flow thereby in the forward position of the valveholder, thereby yielding maximum pressure pulses in the outlet passage.As the valve holder is moved away from the opening, there is aprogressively increasing liquid flow from the working chamber back tothe inlet chamber on the pressure stroke of the piston, thereby allowinga progressive reduction in the pressure of pulses in the outlet passage.

An inlet valve is mounted in the valve holder with the valve head on theworking chamber side of the valve holder and cooperates with a valveseat on the front of the valve holder. The valve head and valve seat areinside the annular region of the pressure regulating means. With thisarrangement, dead space in the working chamber is largely eliminated, sothat room for the formation of air bubbles is largely eliminated.Further, since the annular region of the pressure regulating means isaround the inlet valve, any air bubbles which may form near the annularregion when the pressure regulating means is closed are carried away bywater flowing by the inlet valve head on each suction stroke of thepiston.

Preferably the inlet valve has a valve stem carrying the valve head, andthe valve stem is mounted inside the valve holder and movable in thedirection of movement of the piston. Thus the forces acting on the valvehead and stem are in the direction of movement thereof, so that bendingforces are largely avoided, thereby avoiding excessive wear andpromoting reliable operation over a long period of time even thoughplastic materials are used to reduce cost.

Advantageously the front of the valve holder and the adjacent portion ofthe valve housing have closely-spaced longitudinally extending surfaceswith a plurality of tapered notches in one of the surfaces shaped toprovide corresponding assages of progressively increasing crosssectionalarea for fluid flow from the working chamber to the inlet chamber as thevalve holder is moved away from the opening to the working chamber,thereby producing a gradual change in pressure of the outlet pulses asthe pressure regulating means is adjusted. Preferably thecross-sectional area of the tapered notches is predetermined to yield areduction in outlet pulse pressure which varies linearly with themovement of the valve holder away from the opening. This greatlyfacilitates adjustment of the pressure to suit the users desires.

DESCRIPTION OF THE FIGURES OF THE DRAWINGS An embodiment of theinvention will now be described, by way of example, reference being madeto the figures of the accompanying drawings in which:

FIG. 1 is a longitudinal section through a hydraulic actuator accordingto the present invention;

FIG. 2 is a partial longitudinal section illustrating a modification ofthe hydraulic actuator of FIG. 1;

FIG. 3 is a transverse cross-section on the line III-III of FIG. 1;

FIG. 4 is a transverse cross-section on the line IVIV of FIG. 1;

FIG. 5 is a transverse cross-section on the line V-V of FIG. 1;

FIG. 6 is a graph showing the progression of the crosssectional area ofthe by-pass section according to the regulation position; and

FIG. 7 is a graph which illustrates the variations of pressure accordingto displacements of the pressure regulator of a known hydraulic actuatorand a hydraulic actuator according to the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT As shown in FIG. 1, a hydraulicactuator for connection to a hygiene appliance such as a toothbrush,includes a generally tubular body 5 having a through bore and twopassageways 13, 14 extending through a side wall of the body 5.Passageway 14 is an inlet passageway and communicates with a liquidreservoir (not shown) and passageway 13 is an outlet passageway and isconnected, by means of a conduit 27, to a hygiene appliance (not shown)for example, a hydraulic motor driven toothbrush.

At the left hand end of the body 5, as seen in FIG. 1, the through boreincludes a cylindrical working chamber 26 in which reciprocates a piston1 driven by any known means (not shown). A seal 4 is mounted around thepiston 1 in a recess formed at said left hand end, and a guide plate 3encloses the seal 4 in the recess. The guide plate 3 also centers thepiston 1 in the working chamber 26.

At its opposite end, the body 5, has an inlet chamber 24 which isenlarged to receive an insert 21 having a central threaded hole. Theinsert 21 seats on a shoulder in the inlet chamber 24 and has an endface flush with the end of the body 5. A retaining clip 22 of resilientmaterial engages over a flange surrounding the opposite end of the body5, that is, the right hand end of body 5 and engages the end face of theinsert 21.

An adjustable pressure regulating member and valve holder 19 is screwedthrough the central threaded hole in the insert 21. The member 19includes a first part 19a having a central bore, and a knob 20 extendingoutwardly from the end of the body 5. The knob 20 has flutes 25 toassist in the turning of the member 19. An end portion of the first part19a carries a second part in the form of a sleeve 23 for movementtherewith. The sleeve 23, as seen in FIGS. 1 and 5 is generallycylindrical and is open at the end carried by the first part 19a andformed with an inwardly directed flange at the opposite end. The flangedefines a hole and the outer peripheral edge of the flange is formed asa seating 7 for a valve head 6 of a valve member. Arms 10b extendradially inwardly from a part 10 of the sleeve 23 for supporting abearing part 10a. The valve member has a stem 18 which extends throughand is supported by bearing part 10a. Opposed apertures 15 are formed inthe side walls of the sleeve 23, which apertures 15 are in generalalignment with the inlet passageway 14.

A shoulder 17 is rigidly attached to the valve stem 18 and a spring 12is arranged between the shoulder 17 and an end face of the bearing part1011 to bias the valve head 6 against the seating 7. A seal 16 isarranged over the end of the sleeve 23 adjacent the insert 21.

As will be noted from FIG. 1, an annular region of the front of sleeve23 forming part of the valve holder abuts a corresponding annular regionof the shoulder 8 of the body 5 which forms part of the pump housing,and hence closes the opening in the wall of the working chamber 26opposite the piston 1. Thus no liquid can pass thereby. Rotation of thevalve holder by knob 20 allows the front of sleeve 23 to be moved awayfrom shoulder 8. The periphery of the front end of sleeve 23 has alongitudinally-extending surface which is closely adjacent acorresponding longitudinally-extending surface of body 5. As shown inFIGS. 1 and 3, the logitudinally-extending surface at the front ofsleeve 23 has a plurality of tapered notches 9 which increase incross-section toward the front of sleeve 23.

In the position shown, the small ends of the notches are in engagementwith the adjacent surface of body 5. However, as the valve holder ismoved to the right by rotating knob 20, the effective cross-sectionalarea of the notches progressively increases, thereby allowing aprogressively increasing liquid flow thereby from the working chamber 26to the inlet chamber 24 on the pressure strokes of the piston 1. Thusthe pressure of the liquid pulses in outlet passage 13 is graduallyreduced as the valve holder is moved toward the right. Advantageouslythe notches 9 are shaped so that the reduction in pressure in the outletpassage 13 varies linearly with movement of the valve holder sleeve 23away from the opening in the working chamber 26. This will be explainedfurther in connection with FIGS. 6 and 7.

It will also be noted from FIG. 1 that there is very little dead spacein which air bubbles can accumulate. With the pressure regulator closed,as shown, there is an annular space around the valve head 6 in which airbubbles may tend to accumulate. However, with the valve head 6 on theworking chamber side of the valve seat 7, the flow of water around thevalve head on the suction strokes of the piston tends to wash out airbubbles which may form in this annular space so that excessiveaccumulation of air in this space is prevented.

In operation, the piston 1 is reciprocated in the Working chamber 26such that, when it moves to the left as shown in FIG. 1, liquid is drawnthrough inlet passageway 14 into the inlet chamber 24 through apertures15 into the valve holder and then into the working chamber 26. Movementof the piston 1 in the reverse or compression sense, causes the valvehead 6 to seat on the seating 7 and the liquid in the working chamber 26to be discharged under pressure through outlet passageway 13.

In order to regulate the pressure at which the liquid is discharged,from the body 5, knob 20 can be turned to adjust the position of member19 in the body 5. Adjustment of member 19 permits to a greater or lesserextent a by-pass to be formed between the shoulder 8 and the end face ofsleeve 23 carried by member 19. By increasing the distance between theshoulder 8 and the end face of the sleeve 23, when the piston is makinga compression stroke, some liquid will flow from the working chamber 26through the space between the shoulder 8 of body 5 and the end face ofsleeve 23 and then through notches 9, thereby reducing the pressure ofthe liquid being discharged through the outlet passageway 13.

FIG. 2 illustrates a modification of the piston of the hydraulicactuator, in which the piston 2 consists of a semi-elastic plasticsmaterial having a circular lip 28 which is arranged in a liquid tightmanner in the working chamber 26. With this piston it is possible toeliminate the seal 4 and guide plate 3 described with reference to FIG.1.

FIG. 6 is a graph showing the progressive change in the cross-sectionalarea of the pressure regulating arrangement according to the axialposition L of the sleeve 23. The line P designated the closed positionof the pres sure regulator and P the fully open position. It can be seenthat from the starting (closed) position of the sleeve 23, the area isconstant for about of its displacement then the area change becomespractically linear for about of the displacement and then becomeshyperbolic or exponential according to conditions. Clearly, the numberof tapered notches 9 in the end face of the sleeve 23 can vary and someexperimentation as to the precise shape of the taper may have to beperformed under particular conditions to obtain a linear regulation ofthe pressure.

FIG. 7 is a graph which illustrates the decrease of pressure P in theworking chamber 26 according tothe axial position L of the pressureregulator member 19. The straight line a represents the linear functionof the regulation obtained according to a pressure regulator of thepresent invention. Curve line b represents the function obtained by aknown pressure regulator. As will be noted, curve b shows a rapiddecrease in pressure as the regulator is moved from its closed position,thereby making the adjustment quite ditficult in the higher pressureregion. On the other hand, curve a shows a much more gradual change,thereby facilitating the obtaining of a desired mid-range pressure.

The above described embodiment is a simple hydraulic actuator of smalldimensions which can be assembled quickly and easily without use ofspecial tools or skilled stall. Throughout the specification referencehas been made to the use of the hydraulic actuator as a pump unit,

but clearly and as well known in the art, the hydraulic actuator can beused as a transmitter device, for transmitting linear displacements.

An advantage of the present embodiment is that it permits the regulationof liquid under a pressure in a simple linear and reliable manner, thisis what is usually required when the actuator is used with hygieneappliances.

Further, by reducing the dead space to an absolute minimum, theformation of air bubbles is substantially reduced and is a technicaladvance over known hydraulic actuators.

The hydraulic actuator can be manufactured from plastics material.

We claim:

1. An hydraulic actuator for supplying liquid pressure pulses to a handappliance for body care which comprises (a) a housing having a cylinderand a reciprocating piston mounted therein forming a working chamber,

(b) an outlet passage connected to said working chamber for supplyingliquid-pressure pulses to a said hand appliance,

(c) said outlet passage being free of a discharge valve,

(d) an opening in said housing to said working chamber opposite saidpiston,

(e) an inlet chamber in said housing on the opposite side of saidopening from said piston,

(f) manually-operated pressure regulating means comprising a valveholder adjustably mounted in said inlet chamber for progressiveadjustment toward and away from said opening and for establishing andmaintaining a fixed spacing between said valve holder and opening whenmanually adjusted thereto and thereby bypass a selectable portion of theliquid in said working chamber to said inlet chamber on the pressurestroke of said piston,

(g) the front of said valve holder having an annular region adapted toabut a corresponding annular region of said housing around said openingto prevent liquid flow thereby in the forward position of the valveholder and to allow a progressively increasing liquid flow thereby asthe valve holder is moved away from the opening,

(h) an inlet valve mounted in said valve holder having a valve head onthe working chamber side of the valve holder and a cooperating valveseat on the front of the valve holder,

(i) said valve head and valve seat being inside said annular region sothat liquid flow through the inlet valve on the suction stroke of thepiston washes through the region adjacent the front of the valve holderand said opening to prevent accumulation .of air in said region in theclosed position of said pressure regulating means,

(j) and means for resiliently biasing said valve head toward said valveseat.

2. An hydraulic actuator for supplying pressure pulses to a handappliance for body care which comprises (a) a housing having a cylinderand a reciprocating piston mounted therein forming a working chamber,

(b) an opening in said housing to said working chamber opposite saidpiston,

(c) an inlet chamber in said housing on the opposite side of saidopening from said piston,

(d) an outlet passage connected to the side of said working chamberadjacent said opening for supplying liquid pressure pulses to a saidhand appliance,

(e) said outlet passage being free of a discharge valve,

(f) manually-operated pressure regulating means comprising a valveholder threadedly mounted in said inlet chamber for progressiveadjustment toward and away from said opening and for establishing andmaintaining a fixed spacing between said valve holder and opening whenmanually adjusted thereto and thereby bypass a selectable portion of theliquid in said working chamber to said inlet chamber on the pressurestroke of said piston,

(g) the front of said valve holder having an annular region adapted toabut a corresponding annular region of said housnig around said openingto prevent liquid fiow thereby in the forward position of the valveholder and to allow a progressively increasing liquid flow thereby asthe valve holder is moved away from the opening,

(h) an inlet valve including a valve head and valve stem mounted in saidholder with the valve head on the working chamber side of the front ofthe valve holder and the valve stem inside the valve holder and movablein the direction of movement of said piston,

(i) a valve seat on the front of the valve holder cooperating with saidvalve head and a spring mounted within the valve holder for biasing thevalve head toward the valve seat,

(j) said valve head and valve seat being inside said annular region sothat liquid flow through the inlet valve on the suction stroke of thepiston washes through the region adjacent the front of the valve holderand said opening to prevent accumulation of air in said region in theclosed position of said pressure regulating means.

3. An hydraulic actuator for supplying liquid pressure pulses to a handappliance for body care which comprises (a) a housing having a cylinderand a reciprocating piston mounted therein forming a working chamber,

(b) an opening in said housing to said working chamber opposite saidpiston,

(c) an inlet chamber in said housing on the opposite side of saidopening from said piston,

(d) an outlet passage connected to the side of said working chamberadjacent said opening for supplying liquid pressure pulses to a saidhand appliance,

(e) pressure regulating means comprising a valve holder threadedlymounted in said inlet chamber for movement toward and away from saidopening to bypass a portion of the liquid in said working chamber tosaid inlet chamber on the pressure stroke of said piston,

(f) the front of said valve holder having an annular region adapted toabut a corresponding annular region of said housing around said openingto prevent liquid -flow thereby in the forward position of the valveholder and to allow a progressively increasing liquid flow thereby asthe valve holder is moved away from the opening,

(g) said housing and the front end of said valve holder havingclosely-spaced longitudinally-extending surfaces with a plurality oftapered notches in one of said surfaces shaped to provide correspondingpassages of progressively increasing cross-sectional area for fluid flowfrom the working chamber to the inlet chamber as the valve holder ismoved away from said opening,

(h) an inlet valve including a valve head and valve stem mounted in saidholder with the valve head on the working chamber side of the front ofthe valve holder and the valve stem inside the valve holder and movablein the direction of movement of said piston,

(i) a value seat on the front of the valve holder cooperating with saidvalve head and a spring mounted within the valve holder for biasing thevalve head toward the valve seat,

-(j) said valve head and valve seat being inside said annular region. 4.An hydraulic actuator in accordance with claim 3 8 in which theprogressively increasing cross-sectional area of said tapered notches ispredetermined to yield a reduction in pressure of the liquid dischargedthrough said outlet passage which varies linearly with the movement ofsaid valve holder away from said opening.

5. An hydraulic actuator for supplying liquid pressure pulses to a handappliance for body care which comprises (a) a housing having a cylinderand a reciprocating piston mounted therein forming a working chamber,

(b) an outlet passage connected to said working chamber for supplyingliquid pressure pulses to a said hand appliance,

(c) an opening in said housing to said working chamber opposite saidpiston,

(d) an inlet chamber in said housing on the opposite side of saidopening from said piston,

(e) pressure regulating means comprising a valve holder adjustablymounted in said inlet chamber for movement toward and away from saidopening to bypass a portion of the liquid to the inlet chamber on thepressure stroke of said piston,

(f) the front of said valve holder having an annular region adapted toabut a corresponding annular region of said housing around said openingto prevent liquid flow thereby in the forward position of the valveholder and to allow a progressively increasing liquid flow thereby asthe valve holder is moved away from the opening,

(g) Said housing and the front end of said valve holder havingclosely-spaced longitudinally-extending surfaces with a plurality oftapered notches in one of said surfaces shaped to provide correspondingpassages of progressively increasing cross-sectional area for fluid fiowfrom the working chamber to the inlet chamber as the valve holder ismoved away from said opening,

(h) an inlet valve mounted in said valve holder having a valve head onthe working chamber side of the valve holder and a cooperating valveseat on the front of the valve holder,

(i) said valve head and valve seat being inside said annular region, and

(j) means for resiliently biasing said valve head toward said valveseat.

6. An hydraulic actuator in accordance with claim 5 in which theprogressively increasing cross-sectional area of said tapered notches ispredetermined to yield a reduction in pressure of the liquid dischargedthrough said outlet passage which varies linearly with the movement ofsaid valve holder away from said opening.

References Cited UNITED STATES PATENTS 2,528,833 11/1950 Kelley 4l75543,194,446 7/1965 Miller 4l7296 X 2,429,426 10/ 1947 Phillips et al.92249 X 3,176,595 4/1965 Schwartz 92249 X 1,291,854 1/1919 Haight 4l7296X 2,173,805 9/1939 Hessrnan 4l7296 X 1,943,102 1/1934 Woodruif 4l7296848,277 3/1907 Whitaker 417-558 3,295,748 1/ 1967 Leitgeb 417-440 XCARLTON R. CROYLE, Primary Examiner R. J. SHER, Assistant Examiner U.S.Cl. X.R. 4l7296

